Bilateral Venous Sinuses of Kelch

Case Report https://doi.org/10.5115/acb.21.042 pISSN 2093-3665 eISSN 2093-3673 Bilateral venous sinuses of Kelch Mitchell Couldwell1, Aimee Aysenne1, Joe Iwanaga1,2, Aaron S. Dumont1, R. Shane Tubbs1,2,3,4,5,6,7 1Department of Neurosurgery, Tulane Center for Clinical Neurosciences, Tulane University School of Medicine, New Orleans, LA, 2Department of Neurology, Tulane Center for Clinical Neurosciences, Tulane University School of Medicine, New Orleans, LA, USA, 3Department of Anatomical Sciences, St. George’s University, St. George’s, Grenada, 4Department of Structural & Cellular Biology, Tulane University School of Medicine, New Orleans, LA, 5Department of Neurosurgery and Ochsner Neuroscience Institute, Ochsner Health System, New Orleans, LA, 6Department of Surgery, Tulane University School of Medicine, New Orleans, LA, USA, 7University of Queensland, Brisbane, Australia Abstract: Knowledge of the variant anatomy of the intradural venous sinuses is important to anatomists and clinicians alike. Herein, we report a cadaveric case of the rare venous sinus of Kelch, which some have believed is a remnant of the cranio- orbital sinuses. To our knowledge, only one other cadaveric case has been reported in the extant medical literature. Clinically, knowledge of such a variant venous sinus can minimize misdiagnoses such as when anatomical variations are noted on imaging. Surgically, such an understanding can avoid intraoperative complications such as iatrogenic hemorrhage. Key words: Anatomical variation, Dural venous sinus, Venous sinus of Kelch, Cadaver, Anatomy Received February 25, 2021; Accepted April 5, 2021 Introduction traveling from the superior orbital fissure anteriorly, over the floor of the middle cranial fossa, over the petrous part Unique anatomy and differences in venous drainage of of the temporal bone, to drain into the transverse sinus. The the cranium are important considerations for the clinician and observation of these aberrations may be important in diagnosis and treatment. Clinical cases involving the spread of infection from the middle ear to the intracranial venous system, as well as cases involving chronic otitis media, have all presented with an abnormal presence of a petrosquamous sinuses [1, 2]. Here the authors report an unusual finding of a bilateral presentation of a rare venous sinus, the venous sinus of Kelch. Case Report During the routine dissection of a male cadaver aged 75-year-old at death, a venous sinus (Fig. 1) was identified Corresponding author: Fig. 1. Cadaveric dissection of a left-sided venous sinus of Kelch Joe Iwanaga Department of Neurosurgery, Tulane Center for Clinical Neurosciences, (arrows). Note the middle meningeal veins and artery (MM), superior Tulane University School of Medicine, New Orleans, LA 70112, USA petrosal sinus (SPS), draining vein (DV), optic nerve (CNII), and E-mail: [email protected] internal carotid artery (ICA) for reference. Copyright © 2021. Anatomy & Cell Biology This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. 2 Anat Cell Biol Mitchell Couldwell, et al variant was found on left and right sides (Fig. 2) but the right 17 to 20 mm stage of development, middle and posterior sided sinus was damaged before it could be photographed. plexuses have joined to form the sigmoid sinus while the two Anteriorly, the sinus communicated with the superior oph- parts of the anterior dural plexus; the tentorial sinus, and the thalmic vein, which drained primarily into the cavernous marginal sinus border the expanding hemisphere caudally. sinus. Along the floor of the middle cranial fossa, the venous At the 22 to 24 mm embryonic stage, the supraorbital vein no sinuses communicated with the middle meningeal veins (Fig. 1). longer drains into the stem of the anterior dural sinus, which The superior petrosal sinus traveled medial to the sinus and has diminished and is continuous with the prootic sinus. did not communicate with it. The variant venous sinus was The prootic sinus is a stem of the middle dural plexus which approximately 8 mm in width at its anterior and posterior incorporates into the stem of the posterior dural plexus and extremes but was dilated to 1.2 cm as it crossed over the pe- empties into the sigmoid sinus. Growth of the brain has trous part of the temporal bone. The sinuses were roughly elongated the tentorial sinus, and the marginal sinus now 7.2 cm long. No additional anatomical variations or intracra- constitutes the medial end of the primitive transverse sinus. nial pathology were noted in this specimen. By the 40 mm stage, the cavernous sinuses are developing, and are medial extensions of the prootic sinus which is now Discussion continuous with the newly developed inferior petrosal sinus. A new lateral tributary of the prootic sinus now anastomoses The dural venous sinus of Kelch is a rare venous sinus of with a primitive temporal emissary vein derived from the the skull base and one which has been infrequently reported. sigmoid sinus to form the petrosquamous sinus. At the 60 It effectively unites the veins of the superior orbital fissure to to 80 mm stage, cerebral growth and the development of the the transverse sinus. To our knowledge, cadaveric findings otic capsule has led to the formation of the superior petrosal of this sinus have only been reported once before and these sinus. The primitive transverse sinus has moved backward were of a variant of the sinus. Moreover, a bilaterally present on the sigmoid sinus and has anastomosed with the tentorial sinus has not been reported. sinus. The prootic sinus is now continuous with the petrosquamous sinus. In the adult, remnants of the tentorial sinus Embryology may persist and anastomose with the cavernous sinus which In the early embryo at the 5 to 8 mm stage, the brain is is now joined with the superior petrosal sinus. It would be covered by a continuous plexus which drains both laterally at this stage that one would expect to find the sinus of Kelch and ventrally through three stems, the anterior, the middle, being formed (Fig. 3). The petrosquamous sinus and the and the posterior. By the 11 to 14 mm embryonic stage, each remnants of the prootic sinus become diploic veins and drain subdivision of the brain is drained laterally into the dural plexuses by primitive pia-arachnoidal vessels. During the * * * * Fig. 3. Fetal development of the intracranial venous sinuses. In this schematic drawing, note that the superior ophthalmic vein are developing and are near the more posteriorly located transverse sinus. Fig. 2. Schematic drawing of the bilateral venous sinuses of Kelch This position would be the most likely stage where communication (asterisk) joining veins of the superior orbital fissure to the transverse (dotted line) could occur between these two systems e.g., the venous sinus. sinus of Kelch. https://doi.org/10.5115/acb.21.042 www.acbjournal.org Bilateral venous sinuses of Kelch Anat Cell Biol 3 the dura and bone when the middle meningeal sinus drain ORCID through the foramen ovale and into the sagittal sinus [3]. Mitchell Couldwell: Comparative anatomy https://orcid.org/0000-0002-9981-0788 In primates, there are large evolutionary differences in the Aimee Aysenne: https://orcid.org/0000-0003-4183-1161 orbitotemporal venous sinuses. In primitive primates, these Joe Iwanaga: https://orcid.org/0000-0002-8502-7952 sinuses are large and drain the brain. The cranio-orbital Aaron S. Dumont: https://orcid.org/0000-0002-8077-8992 sinus empties into the postglenoid emissary vein which also R. Shane Tubbs: https://orcid.org/0000-0003-1317-1047 receives drainage from the petrosquamous sinus. In humans, this network of orbitotemporal sinuses is modified and per- Author Contributions sists as part of the middle meningeal vein system which no longer drains the brain, the orbit, or the temporal fossa, and Conceptualization: RST, JI. Data acquisition: RST, JI. Data the petrosquamous sinus is attenuated or non-existent [4]. analysis or interpretation: MC, AA, RST. Drafting of the Due to these evolutionary differences, the presence of a ve- manuscript: MC, AA, JI. Critical revision of the manuscript: nous sinus of Kelch may indicate the remnant of the cranio- ASD, RST. Approval of the final version of the manuscript: orbital sinus in humans [5]. all authors. Sinus of Kelch Conflicts of Interest Reports of a venous sinus of Kelch are rare in the literature. Knott [6] briefly described such a sinus as an acces- No potential conflict of interest relevant to this article was sory sinus which passes backward from the superior orbital reported. fissure over the upper border of the petrous part of the temporal bone to terminate into the transverse sinus. Hol- Acknowledgements linshead [7] stated similarities between the sinus of Hyrtl and the sinus of Kelch and indicated that they may actually The authors sincerely thank those who donated their describe the same structure. More recently, unilaterally pres- bodies to science so that anatomical research could be per- ent sinus of Hyrtl have been described in the literature and formed. Results from such research can potentially increase bilateral occurrences appear to have not been previously mankind’s overall knowledge that can improve patient care. reported [8-10]. We previously reported a unilateral variant Therefore, these donors and their families deserve our high- of the sinus of Kelch found in an 88-year-old at death female est gratitude [12]. cadaver [11]. In this specimen, the sinus of Kelch, which was approximately 3 mm in diameter posteriorly and 6 mm in References diameter anteriorly, drained posteriorly into the superior petrosal sinus rather than into the transverse sinus. On the 1. Klein NE.

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